The antimicrobial effect of different toothpastes on Streptococcus mutans bacteria
Abstract
The persistence of antimicrobial action of toothpaste can be
demonstrated by observing the magnitude of reduction of oral bacteria
caused by the toothpaste. Streptococcus mutans is commonly considered
the main microbe in the formation of dental caries. Toothpastes work to
destroy oral bacteria, S. mutans included, so in order to determine the
most effective toothpaste, it must be discovered which is the most
effective at killing the bacteria. Solutions comprised of 5% S. mutans
bacteria, and 1% and 2% toothpaste were tested to discover which
toothpaste killed the most bacteria, as well as which one had the lowest
LD50 concentration. Solutions were plated and incubated for 24 hours
and colony growth was compared to a control. Colgate Total contains the
active ingredient, Triclosan, which is said to have higher antimicrobial
capabilities than sodium fluoride. It also carries the ADA recommendation
label. Results concurred that the Colgate Total was in fact far superior to
other toothpastes in regard to killing bacteria.
Hellwig, Tyler ; Sethman, Chad R. PhD.
Waynesburg University Department of Biology
Results
2% Toothpaste Conc.
Control
Crest
Aquafresh
Colgate White
Colgate Total
Procedure
•
•
•
•
•
Tests were run to determine the serial dilution that provided a countable
number of colonies (5% conc. bacteria)
Toothpastes were added to bacterial solutions in 2% and 1% concentrations and
vortexed
Solutions were plated via sterile cue tip on Triptocase Soy Agar plates and
incubated for 24 hours; a separate control was made for each trial
Bacterial colonies were counted using a colony counter and compared to the
control to obtain data
•
•
•
•
•
•
Total # of surviving colonies
639
261
325
453
73
1% Toothpaste Conc.
Control
Crest
Aquafresh
Colgate White
Colgate Total
Total # of surviving colonies
265
469
403
484
17
The chart on the left side shows the total number of surviving
colonies when 2% of the overall solution was toothpaste
The chart on the right shows the same data for 1% overall toothpaste
solution
Colgate Total far exceeded the ability of any other toothpaste to kill
bacteria
Every toothpaste was able to kill at least 50% of the bacteria at these
concentrations (Aquafresh and Crest = 2%; Colgate Total 1%) except
Colgate White
While controls did vary greatly overall toothpastes were less effective
at the lower concentration with the exception of Colgate Total which
actually was more effective
One trial had to be omitted due to an uncountable number of colonies
A 2-way proportionality Z-test was run to test significance and all pvalues < .001
Introduction
Discussion
•
•
•
•
Experimentation proved that the Colgate Total was in fact far more
effective at killing S. mutans bacteria than the other toothpastes tested.
Colgate Total killed over 90% of the cultured S. mutans while the next
leading toothpaste was just over 20%. Colgate Total also had the lowest
LD50 concentration of toothpaste. Even though the results strongly
suggest that for the highest quality dental care consumers should use
Colgate Total, there is another aspect of the toothpaste consider. While
the active antimicrobial ingredient in Colgate Total, Triclosan, has been
approved by the FDA for usage in consumer products there is a swell of
controversy surrounding the chemical. Recent studies, have suggested
that Triclosan can alter hormone regulation in animals (although no
human testing has confirmed this) as well as causing bacterial resistance
to antibiotics. In lieu of these findings the FDA has continued research
into these allegations, yet at the moment Triclosan is still considered safe
for human use. Triclosan (Colgate Total) has obvious advantages in killing
bacteria and preventing oral disease, yet it is ultimately up to the
consumer to decide if the benefits outweigh the potential risk.
Streptococcus mutans is the leading cause of dental caries worldwide
S. mutans is most cariogenic of all oral Streptococci
Metabolizes sugar to produce acid that causes cavities
3 steps to good oral health
• Flossing releases bacteria between gums
• Mouthwash provides a layer of prevention against
plaque
• Toothpaste effectively destroys oral bacteria
• Which brand of toothpaste kills S. mutans most effectively
• Colgate Total contains relatively new ingredient called Triclosan
• Triclosan is found in antibacterial products such as soap,
body wash, detergents, and toothpastes
• Colgate Total also carries with it an ADA
recommendation label
This graph shows the concentration of toothpaste it took
to kill over 50% of the bacteria.
*Colgate White never achieved an LD50 in any of the
concentrations tested
This graph shows the total percentage of bacteria killed in
both trials in comparison to the control.
*The final colony count for Colgate White was higher than
the control which is the reason the graph shows 0%.
Acknowledgements
This graph shows the total number of surviving colonies
for each parameter.
Dr. James Bush; Professor of Mathematics, Computer Science, and
Physics
Nancy Wrick; Program Specialist